The present invention relates to a device and method for determination of a required length of an epidural catheter for continuous epidural anesthesia.
It is known that a standard procedure for the continuous epidural anesthesia requires localization of the epidural space by the epidural needle, then insertion of the epidural catheter through the epidural needle, then removal of the epidural needle and positioning of the catheter within the epidural space. Proper positioning of the epidural catheter is 2.5-3 cm inside the epidural space, and this proper position will minimize occurence of complications. Since the distance between the skin and the epidural space varies from 3 to 8 cm, every case requires a time consuming calculation of the length of the catheter with the graduated epidural needle and catheter.
It is known that in this procedure for a continuous epidural anesthesia when the epidural catheter is utilized, the catheter in the epidural space can be the cause of various iatrogenic complications. In order to avoid leaving too great a length in the lumbar epidural space during epidural anesthesia, graduated Tuochy needles can be used together with graduated epidural catheters. On the latter, a special marking shows that, when it reaches the needle hub, the catheter tip is at the needle bevel. Approximately 5-7 cm of the catheter length is introduced into the epidural space. The needle is removed and placed upside down next to the catheter with the hub in contact with the patient's skin. In this position the distance between the special marking on the catheter and the graduation on the needle which marks the skin level is equivalent to the length of the catheter in the epidural space. This distance and therefore the catheter length can then be reduced to about 4 cm by carefully withdrawing the catheter. Knowing exactly how much of the catheter is within the epidural space can be of particular importance whenever that space is uncommonly far from the patient's skin, due to obesity, oedema, use of paramedian route or a very oblique angle of the needle in the sagittal plane. The above described method is quite complicated and it is to be understood that it is desirable to improve the same.
In the stressful atmosphere of the operating room the above specified measurements and calculations present unnecessary hardships and usually are done with a great degree of inaccuracy.